JP4459686B2 - Satellite signal retransmission system - Google Patents

Description

The present invention relates to a satellite signal retransmission system using a retransmission antenna for retransmitting satellite signal received.

  In order to be able to provide a broadcasting service even to a blind area such as a living room where a broadcast signal radiated from a satellite or a gap filler does not reach within a broadcasting area of satellite digital audio broadcasting, Transmit antennas and satellite signal retransmission systems have been devised. This is because a broadcast signal of any one of the two broadcast signals directly from the satellite or via the gap filler is received, and the received broadcast signal is further reradiated toward the insensitive area by the retransmission antenna. Is. The same 2.6 GHz band frequency is used for these two systems of broadcast signals. Therefore, it is only necessary to configure the receiving device according to this one type of frequency, and the device configuration can be simplified.

JP 2004-007531 A

  However, since the radiation levels of the two types of broadcast signals are originally standardized so as to be different, the input level range at the time of reception varies greatly depending on which one is received. Accordingly, the signal retransmission power radiated from the retransmission antenna may change. In that case, the output level of the retransmission signal may deviate from a predetermined output value range depending on conditions.

The present invention has been made in view of the above problems, even when the input level of the broadcast signal received is changed, the satellite signal again using the re-transmission antenna that can stably emit an approximately constant output level of the signal It is an object to provide a transmission system.

In order to solve the above problem, a satellite signal retransmission system according to the invention of claim 1 includes a right polarization signal reception unit and a left polarization signal reception unit that receive BS and CS signals, and the received right polarization signal The signal is IF-converted at a local frequency of approximately 10.678 GHz, and the received left-polarized signal is IF-converted at a local frequency of approximately 9.576 GHz, and the received signal that has been IF-converted is mixed and output. 1 mixing means, a satellite broadcasting receiving antenna unit for receiving a 2 GHz band mobile satellite signal and outputting it without IF conversion, and an output signal from the satellite broadcasting receiving antenna unit for mobile unit The second mixing means for mixing the signal from the first mixing means, and the signal mixed by the second mixing means is transmitted through one signal cable and drawn indoors, and connected to the drawn signal cable. An AGC amplifier that amplifies a satellite reception signal for a mobile unit in the 2 GHz band and outputs a transmission signal having a predetermined output level, a signal transmission path that attenuates a signal output from the AGC amplifier by a predetermined amount, and the signal And a re-transmission antenna unit that re-radiates the signal attenuated in the transmission line at a predetermined radiation level.

Satellite signal retransmission system according to the invention of claim 2, said AGC amplifier, said signal transmission line, formed by integrally forming, and the retransmission antenna unit.

Here, the satellite broadcast signal for mobile objects indicates a mobile broadcast signal in a so-called mobile broadcast system. The mobile broadcast system includes a broadcast provider's broadcast center that transmits a mobile broadcast signal in the 12 GHz band toward a mobile broadcast satellite in the sky, and a received mobile broadcast signal in the 2.6 GHz band (2.630 GHz to 2.655 GHz) and The mobile broadcast satellite that radiates toward the ground as a 12 GHz band mobile broadcast signal and the 12 GHz band mobile broadcast signal emitted from the mobile broadcast satellite are received and converted to the 2.6 GHz band (same frequency as the mobile broadcast satellite). An area where mobile broadcast signals of mobile broadcast satellites do not reach directly, that is, a gap filler that re-radiates to a dead area, and a mobile broadcast signal of 2.6 GHz band that is radiated from the mobile broadcast satellite or re-radiated from the gap filler. The broadcast user's mobile receiving terminal (hereinafter referred to as “PDA”) Those consisting comprise to) and. The AGC amplifier refers to an automatic gain control amplifier, that is, a high frequency amplifier having a function of adjusting and amplifying the gain according to the reception level.

According to the first aspect of the present invention, even when the input level of the received broadcast signal fluctuates, a signal with a substantially constant output level can be radiated stably from the retransmission antenna unit.

  According to the second aspect of the present invention, since the AGC amplifier, the signal transmission path, and the retransmission antenna unit are integrally formed, the installation space can be reduced.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. FIG. 1 is a layout diagram showing a reference example of a retransmission antenna with an AGC amplifier. In the figure, 2 is a mobile broadcast receiving antenna unit (hereinafter simply referred to as a receiving antenna unit) serving as a mobile satellite broadcasting receiving antenna unit that receives a satellite digital audio broadcast signal that is a mobile broadcast signal, and 8 is received by the receiving antenna unit 2. A re-transmission antenna unit that re-radiates the mobile broadcast signal, 17 is a dead area such as a dwelling unit or an underground mall, and 20 is a mobile having a predetermined output level by amplifying the mobile broadcast signal input within a predetermined level range. An AGC amplifier that outputs a broadcast signal, 21 is a signal cable as a signal transmission path for attenuating a signal output from the AGC amplifier 20 by a predetermined amount, and 30 is a PDA.

  The receiving antenna unit 2 includes a so-called planar antenna element unit formed in a size and shape that can be received at a frequency of 2.6 GHz band, and a radome unit that covers the radiation surface side of the planar antenna element unit. The receiving antenna unit 2 is driven by a DC 5V power source and is configured to have an absolute gain of 2.5 dBi as a characteristic. The receiving antenna unit 2 is installed at the window in the dwelling unit with the radome portion facing the outside.

  The re-transmission antenna unit 8 includes a planar antenna element formed in a size and shape capable of re-radiating a mobile broadcast signal transmitted by the signal cable 21 at a frequency of 2.6 GHz band, and a radome covering the radiation surface side of the planar antenna element. And is composed of. The retransmission antenna unit 8 is configured to have an absolute gain of 2.5 dBi as a characteristic. The re-transmission antenna unit 8 is installed near the ceiling of a room in the dwelling unit with its radome portion facing downward.

  The AGC amplifier 20 is driven by a DC5V power supply, and amplifies the signal so as to output a signal with a constant output level of −40 dBm when the input mobile broadcast signal is within a predetermined input level range of −87 dBm to −15 dBm. It is made possible. The signal cable 21 is a coaxial cable that attenuates a signal of a constant output level output from the AGC amplifier 20 by 2 dB, for example, a 2.5 C cable having a cable length of 3 m. The PDA 30 includes a built-in antenna unit that secures a reception level of −96 dBm. It is also possible to use a 4C low-loss coaxial cable as the signal cable 21. In this case, the cable length is set to about 4 m in order to secure an attenuation of 2 dB.

  The mobile broadcast signal radiated from the mobile broadcast satellite and the gap filler in the 2.6 GHz band and received by the receiving antenna unit 2 is drawn into the AGC amplifier 20 via the signal cable 9 connected to the output end. The mobile broadcast signal drawn into the AGC amplifier 20 is reshaped into a 2.6 GHz band signal and amplified to a predetermined output level by the AGC amplifier 20. The mobile broadcast signal is sent from the AGC amplifier 20 to the re-transmission antenna unit 8 through the signal cable 21 and is 2.630 GHz-2 in the same frequency band as the frequency of the mobile broadcast signal radiated from the mobile broadcast satellite and the gap filler. Re-radiated from the retransmission antenna unit 8 into the dead area 17 as a .665 GHz retransmission signal. The retransmission signal re-radiated from the retransmission antenna unit 8 is received by the PDA 30 in the dead area 17, and the user is provided with a mobile broadcast.

FIG. 2 is a level diagram showing signal levels of mobile broadcast signals at measurement positions A to D on the transmission path from the receiving antenna unit 2 installed indoors to the AGC amplifier 20. Point A is the receiving end of the receiving antenna unit 2, point B is the output end of the receiving antenna unit 2, point C is the output end of the signal cable 9, and point D is the output end of the AGC amplifier 20. The ○ mark in the figure indicates the measured value when the mobile broadcast signal re-radiated from the gap filler is received, while the △ mark indicates the measured value when the mobile broadcast signal directly radiated from the mobile broadcast satellite is received. Each one is shown.
From this figure, the input level of the mobile broadcast signal input to the AGC amplifier 20 at the point C is -76 dBm to -15 dBm, and is included in the predetermined input level range -87 dBm to -15 dBm. It can be seen that the output level is a constant output of -40 dBm.

According to the retransmission antenna with an AGC amplifier, in the service area of the mobile broadcast satellite, it is possible to provide a service by radiating a mobile broadcast signal even to a dead area 17 such as a dwelling unit or an underground shopping center that cannot be covered with a gap filler. . At the time of provision, since the AGC amplifier 20 is provided in front of the re-transmission antenna unit 8 via the signal cable 21 having a predetermined transmission loss, the output level of the radiation signal output from the mobile broadcast satellite (at the point A) Even when receiving mobile broadcast signals with greatly different radiation output levels, such as -96 dBm) and the same output level of the gap filler (-35 dBm at point A), the output level is adjusted within an appropriate range. Therefore, the output level of the broadcast signal re-radiated from the re-transmission antenna unit 8 at the subsequent stage can always be suppressed to a predetermined value or less.
In addition, a combination of the signal cable 21 and the AGC amplifier 20 can radiate a signal having a constant output level from the retransmission antenna unit 8 more stably.

  As shown in FIG. 3, in the retransmission antenna with an AGC amplifier, the reception antenna unit 2 is not limited to being installed indoors but may be installed outdoors. The re-transmission antenna in this figure is composed of the receiving antenna unit 2, a signal cable 31a composed of a 2.5C cable having a cable length of 4 m connected thereto, a connection cable 31b for a gap, and a 2.5C cable having a cable length of 10 m. The signal cable 31c, the AGC amplifier 20, the signal cable 21 having a cable length of 3 m as a transmission line, and the retransmission antenna unit 8 are configured. In this case, since the receiving antenna unit 2 is installed outdoors with a relatively strong electric field strength, it is possible to improve the receiving sensitivity.

FIG. 4 is a level diagram showing signal levels of mobile broadcast signals at measurement positions A to F on the transmission path from the receiving antenna unit 2 installed outdoors to the AGC amplifier 20. Point A is the receiving end of the receiving antenna unit 2, point B is the output end of the receiving antenna unit 2, point C is the output end of the signal cable 31a, point D is the output end of the gap connection cable 31b, and point E is the signal cable 31c. The output terminal F and the point F are the output terminals of the AGC amplifier 20. Other symbols are the same as those in FIG.
From this figure, the input level of the mobile broadcast signal input to the AGC amplifier 20 at point E is −82 dBm to −21 dBm, and the output level of the AGC amplifier 20 is a constant output of −40 dBm, as in the case of indoor installation. You can see that

Next, FIG. 5 is a layout diagram showing another reference example of re-transmitting antenna with A GC amplifier. This retransmission antenna with an AGC amplifier is configured such that the retransmission antenna unit 8 is integrated with the cradle 25. Here, the cradle refers to a connection base on which the PDA 30 is placed and connected to a desktop personal computer or the like so as to be able to transfer data. It also has a function of charging the PDA 30. In this case, the AGC amplifier 20 connected to the re-transmission antenna unit 8 is formed so as to be able to amplify so as to output a signal having a constant output level of −65 dBm. Other configurations are the same as those in FIG. According to the retransmission antenna with an AGC amplifier, it is possible to obtain the same operational effects as those in FIGS.

  Next, FIG. 6 is a configuration explanatory view showing an embodiment of a satellite signal retransmission system according to the present invention, and FIG. 7 is a block diagram of a satellite signal receiving antenna. 1 is a satellite signal receiving antenna for receiving a BS signal from a first satellite and a CS signal from a second satellite, and 2 is a satellite broadcasting receiving antenna for a mobile object that receives a satellite digital audio broadcast signal that is a satellite broadcast signal for a mobile object. (Hereinafter simply referred to as a receiving antenna unit) 3 is a booster, 6 is a mixer as a second mixing means, 7 is a branching unit, 8 is a retransmitting antenna unit for re-radiating the received signal, and 17 is a dwelling unit or an underground shopping center. The insensitive area is shown.

As shown in the block diagram of FIG. 7, the satellite signal receiving antenna 1 is composed of a pair of receiving probes 10, a converter unit 11, and a mixing unit 12 as a first mixing unit. It consists of a first probe 10a for reception and a second probe 10b for right polarization reception. The converter unit 11 includes a first local oscillator unit 11a and a second local oscillator unit 11b, and the signal received by the first probe 10a and the signal received by the second probe 10b are IF with independent local frequencies. Converted. Reference numeral 13 denotes an amplifier circuit.
The mixing unit 12 is provided with a high-pass filter 12a on the first probe 10a side and a low-pass filter 12b on the second probe 10b side for mixing.

The left polarization signal received by the first probe 10a is IF-converted at the local frequency 9.57638 GHz of the first local oscillator 11a, and the right polarization signal received by the second probe 10b is the second local oscillator 11b. IF conversion is performed at a local frequency of 10.678 GHz. Thus, the BS and CS signals received in the frequency spectrum shown in FIG. 8A are IF-converted into the frequency band shown in FIG. 8B, outputted to the signal cable 9a which is a single coaxial cable, and transmitted. The
Then, the satellite digital audio broadcast signal received by the receiving antenna unit 2 is amplified and output by the booster 4 without being frequency-converted, and is mixed with the BS and CS signals by the mixer 6, and FIG. Is drawn indoors with one signal cable 9b in the frequency spectrum shown in FIG.

  As shown in the frequency spectrum of FIG. 8 (c), the satellite digital audio broadcasting signal has a relatively narrow band of 2.630 to 2.655 GHz, so this frequency is the high-end frequency of 2.611 GHz of the BS left polarization signal. The CS left polarization signal can be placed in a guard band between the low-end frequencies of 2.673 GHz, and even if the reception frequency has a BS left polarization signal, it affects the BS and CS signals with a single signal cable. The satellite digital audio broadcast signal can be mixed and transmitted without any problem.

  The re-transmission antenna unit 8 is connected to the signal cable 9b indoors via a branching unit 7 via a signal amplifier 8c as an AGC amplifier. The retransmission antenna unit 8 is connected to a signal amplifier 8c by a signal cable 9. The signal amplifier 8c is configured to pass a signal in a frequency band of 2.630 GHz to 2.665 GHz, and amplifies the signal in the frequency band. In this way, the re-transmission antenna unit 8 is re-radiated at 2.630 GHz to 2.665 GHz, which is the same frequency as the satellite digital audio broadcasting frequency transmitted from the satellite.

As described above, the satellite signal receiving antenna 1 performs IF conversion on the received left polarization signal above the right polarization signal on the frequency axis, so that it is separated even if there is a frequency band overlapping the left and right polarization of the satellite signal. Thus, it is possible to transmit all received signals with one signal cable. Therefore, when the signals from the first satellite and the second satellite are BS and CS signals, even if the reception frequency has a BS left polarization signal, there is no common frequency band, and all signals can be obtained with one signal cable. A received signal can be transmitted.
At that time, the left polarization signal is IF-converted at 9.57638 GHz, and the right polarization signal is IF-converted at 10.678 GHz. Therefore, even if the reception signal has a BS left polarization signal, 2.63 A satellite digital audio broadcasting signal of up to 2.655 GHz can be mixed and transmitted.

  Therefore, satellite digital audio broadcast signals can be drawn indoors without newly drawing signal cables, and satellite digital audio broadcast signals can be re-radiated. Can receive audio broadcasts. Needless to say, if the mobile device is directly connected to the drawn signal cable, the satellite digital audio broadcast can be received without providing the retransmission antenna unit 8. Also, since the received signal is transmitted and transmitted without frequency conversion, a converter circuit is not required, and a satellite signal retransmission system can be easily configured. For example, it is suitable for an area such as an underground mall where re-radiated radio waves do not leak.

  In the service area of the satellite digital audio broadcasting satellite, when the service is provided, the AGC amplifier 20 is provided in front of the re-transmission antenna unit 8 via the signal cable 21 having a predetermined transmission loss. The output level of the AGC amplifier 20 can be adjusted within an appropriate range as long as the output level of the radiation signal output from the same output level of the gap filler and the output level of the gap filler are within the predetermined output level range. The output level of the broadcast signal re-radiated from the transmission antenna unit 8 can always be kept below a specified value.

Here, a characteristic diagram of a transmission distance of the re-radiated signal output from the retransmission antenna portion 8 of the engaging Ru satellite signal retransmission system of the present invention in FIG. From this figure, it can be seen that if the standard value of the reception level is −96 dBm or more, a transmission distance of at least 5 m can be secured in the radiation direction of the retransmission antenna unit 8. Further, if the execution value is −101 dBm or more, a transmission distance of 10 m can be secured.

The present invention is not limited to the above-described embodiment, and can be implemented by appropriately changing the shape and configuration of each part without departing from the spirit of the present invention, as exemplified below. .
(1) In the retransmission antenna with an AGC amplifier, the AGC amplifier, the signal transmission path, and the retransmission antenna unit are not limited to separate units, and may be integrally formed. In that case, the installation space can be reduced. For example, even when the installation space is installed on the ceiling, the feeling of pressure caused by the installation can be relatively removed, and the user's feeling of use can be improved.
(2) The signal transmission path in the case of (1) is not limited to a coaxial cable as long as the signal output from the AGC amplifier is attenuated by a predetermined amount, and the attenuation may be adjusted by providing an attenuator or the like. . According to this signal transmission line, the transmission loss caused depending on the length of the cable can be eliminated because the use frequency is high.

It is a layout figure which shows one reference example of the retransmission antenna with A GC amplifier. FIG. 2 is a level diagram of the retransmission antenna with an AGC amplifier shown in FIG. 1. It is a layout figure which shows one reference example of the retransmission antenna with A GC amplifier. FIG. 4 is a level diagram of the retransmission antenna with an AGC amplifier shown in FIG. 3. It is a layout figure which shows another reference example of the retransmission antenna with A GC amplifier. 1 is an explanatory diagram illustrating a configuration of an embodiment of a satellite signal retransmission system according to the present invention. It is a block diagram of the satellite signal receiving antenna shown in FIG. The change of a received signal is shown, (a) is a reception frequency spectrum of BS and CS signals, and (b) is a frequency spectrum obtained by IF conversion of BS and CS signals. (C) is a frequency spectrum obtained by adding a satellite digital audio broadcast signal to an IF-converted BS and CS signal. It is a characteristic diagram showing the transmission distance of the re-radiated signal output from the re-transmission antenna portion of the engaging Ru satellite signal retransmission system of the present invention.

Explanation of symbols

  1. Satellite signal receiving antenna 2. Mobile satellite broadcasting receiving antenna (receiving antenna unit) 6. Mixer as second mixing means 8. Retransmit antenna unit 9a, 9b signal Cable 10 ··· Probe 10a · · 1st probe 10b · · 2nd probe 11 · · Converter part 11a · · · First local oscillator 11b · · · 2nd local oscillator 12 · · · 1st Mixing section as mixing means, 17 .. Insensitive area, 20... AGC amplifier, 21 .. Signal cable as signal transmission path, 30.

Claims (2)

It has a right polarization signal reception unit and a left polarization signal reception unit that receive BS and CS signals, performs IF conversion on the received right polarization signal at a local frequency of approximately 10.678 GHz, and receives the received left polarization signal An antenna unit that performs IF conversion at a local frequency of approximately 9.576 GHz,
First mixing means for mixing and outputting the received signal after IF conversion;
A mobile satellite broadcast receiving antenna unit that receives a 2 GHz mobile satellite broadcast signal and outputs it without IF conversion;
Second mixing means for mixing the output signal from the satellite broadcast receiving antenna unit for mobile and the signal from the first mixing means;
The signal mixed by the second mixing means is transmitted through a single signal cable and drawn indoors, and connected to the drawn signal cable to amplify the satellite reception signal for 2 GHz band mobile objects to a predetermined output level. An AGC amplifier that outputs a transmission signal of
A signal transmission path by a predetermined amount attenuates the signal output from the AGC amplifier,
And re-transmitting antenna unit which re-radiate the signal attenuation by the signal transmission line at a given radiation level,
Comprising
A satellite signal re-transmission system. Said AGC amplifier, said signal transmission line, formed by integrally forming, and the retransmission antenna unit,
The satellite signal retransmission system according to claim 1.

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